Concepts Of Physics MCQ Edition [Volume 1]PhysicsGravitation
A planet has a radius R₁ , and a satellite revolves around it in a circle of radius R₂ . The time period of revolution is T . Determine the acceleration due to the planet's gravitation at its surface.
Options
- A2 ^2 R₂^3 T^2 R₁^2
- B4 ^2 R₁^3 T^2 R₂^2
- C4 ^2 R₂^2 T^2 R₁
- D4 ^2 R₂^3 T^2 R₁^2
Correct answer
D. 4 ^2 R₂^3 T^2 R₁^2
Step-by-step solution
Let M be the mass of the planet. The acceleration due to gravity at the surface of the planet is given by g = GM R₁^2 . For a satellite revolving in a circular orbit of radius R₂ , the time period T is given by T = 2 R₂^3 GM . Squaring both sides, we get T^2 = 4 ^2 R₂^3 GM , which yields GM = 4 ^2 R₂^3 T^2 . Substituting this value of GM into the expression for g , we obtain g = 4 ^2 R₂^3 T^2 R₁^2 .